John, Yes it is worth it, it is called return on investment.

Often, things we do not understand anger us, please relax, and rather than lash out, consider things from different prospective.

Best Wishes

We built a new home 3 years ago. We have a lot of glass. The electric bills are very high. We did not fully consider utility cost when we designed and built the home.

A colonial with highly rated windows and good insulation all around should be fairly efficient.

If you are using an architect, make sure he or she understands your desire for efficiency. Then it is your job not to "trade away" that efficiency when it comes time to make compromises with your plan.

We do keep the house cooler in the winter and warmer in the summer to reduce cost.

I live in a midcentury glass box type house in the desert. My electric bills are not bad, given the size of the house. The reason, I think is because of the large overhanging patio roof on the South and West, and the screen block on the East. I would speak with your architect. I imagine that good quality windows, properly sealed, would diminish the utility cost. Maybe placing landscaping (trees) in strategic locations to help cut down on direct sun rays will in the summer will also help. I bet there are ways to miminize the cost of having lots of windows. I would personally prefer more glass and a little higher utility bill.

i would look many places for info to try to reduce heat and cold. the main places that cost money are the dryer, cooling and heating and oven. there are many things they do not tell you. like once i heard on this old house that they do not include wood windows in the studies, because they are the best but hardest to get. never told you that did they? someone could have fixed your sash weights, the biggest problem, pumped in extra insulation and you would be much warmer. don't get windows that don't open. a whole house fan that actually thumps your windows when it goes on can delay your ac by a few weeks.

hang the laundry as much as possible.

we lived on the far side of a swamp. no trees anywhere. got to be 90s often. we took inexpensive roll up shades and hung them on the 3rd step out from our sliding glass doors, temp was 10 degrees cooler. use big porches, even better.

I love windows. At lot. We have over 60 and didn’t want an attached garage, just we could have them on more walls.

But.... sometimes when I am in older homes (like from the colonial period), I love the feel of rooms with large, fewer windows. They seem to frame the view and be a feature in the room, instead of a wall of glass. Better for energy costs too, I would think, and easier to arrange furniture.

There are a lot of historical homes in your area. I would go see how they feel to you. Just something to consider. :)

https://www.houzz.com/magazine/energy-efficient-windows-decipher-the-ratings-stsetivw-vs~2206808

https://www.energy.gov/energysaver/energy-saver

Energy audit and calculations, based on a variety of options for the architectural envelope.

Windows are usually good, as long as one likes natural light. The optimal orientation for living, dining and kitchen spaces with the most windows and most frequent daily use is...facing south. Facing south allows for many design options for summer and winter passive solar design.

Facing west is the worst possible orientation. Sell the house and move before you do west facing windows.

How old is the current part of the house? I wonder if the insulation you have in the current house is more of an issue than your windows.

i live in an old house (1870) with new windows (pella solid wood). in winter we snug up to the windows, they let in less cold air than the walls.

energy audit says there is not going to be a payback in our lifetime for insulating the walls, just more comfortable. as long as we can sit by a window we're happy.

If you can’t afgord to double your utility bill, there is no way you can afford the million dollar doubling in size of your current home either.

I don’t know that it’s a matter of can’t afford. I can afford a lot of things on which I simply don’t want to spend my money.

OP, I think that it’s smart of you to be questioning this before diving in. You’ve already got significant utility bills and I personally wouldn’t want to have mine much higher without really good reason.

you know you should study old houses. my mother had a giant window that did not open. it cost her hundreds to cover. my 110 year old house had a six foot tall 3 ft wide window in every wall. easier to cover let in lots of light when wanted.

Our current home is so tight that I can't hear a car coming up our gravel driveway when the windows and doors are closed. These are mostly casement windows that latch tight to their frames. All our windows and 15 French doors are Pella with between-the-glass shades. The shades (and heavy window casings) meant I didn't need to spend on expensive window 'treatments' except in bedrooms.

Our 'starter' home -- tract house, c. 1950 -- had no insulation between drywall and brick exterior. It also featured efficient heat-exchanging aluminum frame windows! We blew in insulation and changed out windows. BIG difference in comfort and heating/cooling expenses. That house also had a family room addition with electric baseboard heating -- and no air returns. We ran that baseboard heat one month...until we got the electric bill.

Before I started adding/replacing windows and doors, I was running $200 a month in the summer. That was 10 years ago and yes, my house was built in the 60s with no insulation to the brick walls which is about 70% of exterior area. I have to say I enjoy having lots of windows. But what has been bothering me for the past couple of years is that my electric bill started having a section for comparing with my neighbors. My bill is 50-100% higher than my neighbors. That and the newly decided addition project finally pushed me over to be looking at this critically. At the moment, I am still leaning towards the go-big idea. Well, I will definitely add maximum amount of solar capacity to my budget to offset that bigger footprint and maybe even to net out my electric bill.

oh, i get that comparison.... you have to be careful assessing your use from that. are all of your neighbors in single family homes of a similar square footage? our 5 bedroom house is being compared to 2 bedroom condos... no wonder we use more!

My neighborhood is a big subdivision with similarly sized homes. I added 40% more glass area including a couple of skylights. Overall, my house is not too drafty that would ring a bell when it comes to why it takes so much energy to run. That is why I decided to take a look to be comfortable that nothing is going to change my hindsight dramatically that cause me to regret. Thanks for all of your comments. I feel that this is just a lifestyle issue that is not going anywhere.

I live in a 1956 MCM ranch with huge overhangs that block the summer sun and heat my house in the winter when the sun is lower. I would never give up my large windows to save money but proper planning is essential .

That was 10 years ago and yes, my house was built in the 60s with no insulation to the brick walls which is about 70% of exterior area.

That's your problem. Not the windows. Figure out a way to get the walls insulated. How do I know? Because I'm in a rental that has no insulation in the walls and it's cold in winter. The windows are fine.

If you live in the part of the DC suburbs that BG&E services, I likely recommend their energy audit. It cost $100 but was very thorough. They discovered air leaks around two of my doors and had other suggestions on how to reduce energy usage. A big one for me is air leaks from my second floor into/out of attic through places like ceiling light fixture. They guaranteed that fixing these would save me about $300 each year. I'm going to have it done in the fall. The audits are done by third party companies and my inspector was very knowledgeable. That person might be able to give you advise on your addition.

By comparing with my neighbors having the same types of house profile other than the 40% more glass area, I should be able to conclude that $150 extra utility is the result of having extra glass area, right? So it will give me some yardstick to say my new addition should cost at least $150 -$200 on utility having the same amount of glass as existed?

Nope! You don't know the insulation value and type of glazing of your neighbor's house, so you can't compare it to yours.

The simplest and most accurate approach to your question is to call you local utility company and ask for assistance for an energy audit of your house and plans.

It's really simple to do.

You could call the utility people and have them inspect/calibrate your meter, just to make sure. If digital, then no calibration needed.

You might also be thinking the Windows are causing the hike, when in reality it is all the electronic toys. They are power guzzlers. Have you had your a/c looked at? If running (or over-running needlessly), it’s costing ya.

I used to be in the energy industry and the surcharges that are hidden by the utilities would shock you. It felt awful to buy/sell natural gas for $1/mmbtu and see my power statement where I was indirectly paying $10-12/mmbtu

a pool or jacuzzi pump are huge energy hogs as well.

My neighborhood is a big subdivision with similarly sized homes. I added 40% more glass area including a couple of skylights.

If I were buying a house in your subdivision, and had the choice of House A, House B, and House D with a standard amount of windows, and House C with skylights and 40 percent more windows, I would be choosing House C.

I get those things from LG&E constantly. Yes, my utility costs are higher than my neighbors as I'm home all day and do not want the temp at 65 or 85 - neighbors all work all day and leave the thermostat accordingly. I also like to sleep in a refrigerator; in the winter, my upstairs HVAC is rarely even on; in the summer, it is going full blast to keep the room cool for sleeping. I could care less. I can afford the bill and want my house to be comfortable. I have 21 windows in my 1948 brick house. They are Marvin windows which I put in in the past 6-8 years. I have good insulation in my attic - I don't worry about the brick walls as I have large trees in my yard.

I'm very tired of those comparisons from LG&E. So long as I pay my utility bill in full and on time, it's really none of their business how I compare to my neighbors. BTW, my neighbors are all much wealthier than I am. Should they have to dispose of some of this? Ridiculous....